Milev, Oleg, José Luis Vázquez, Desislava Ivanova, and Ivan Georgiev. “Innovative Strategies in the Management of Alternative Tourism”. Responsibility and Sustainability 2, no. 1 (April 1, 2014): 65–70. Accessed April 23, 2026. https://responsibility-sustainability.org/index.php/R-S/article/view/30.